Warning over plasterboard waste risk

In AN attempt to reduce costs on bedding materials, some farmers have started to use re-cycled plaster board waste but as the death of four cattle on a Borders farm has demonstrated there are dangers with this material if it is used in the wrong conditions.

During a recent dry spell, the unidentified beef producer took advantage of the conditions to begin emptying some of the slurry stored under the slatted floors of his beef sheds. Having taken out just two or three loads he returned to find four of his large steers dead. A post mortem found they had all been suffocated by hydrogen sulphide gas.

The mixing and handling of slurry had produced the toxic gas which is invisible, although it has a smell like rotten eggs. In a confined area it rapidly suffocated the cattle and could equally have suffocated any humans who had come into the shed.

Adding silage effluent to slurry had increased the risk as the nutrients in the effluent feed the bacteria in the slurry which then produced the hydrogen sulphide gas.

What was unique in the Border’s case was that the farm had just started using waste plaster board containing high levels of gypsum to help dry up the straw bedding being used in other buildings.

However, heavy rain had washed some of that gypsum into the slatted shed and down into the slurry store. Gypsum, or calcium sulphate, contains high levels of sulphur which encourages the bugs to produce even greater amounts of hydrogen sulphide from the slurry.

Scott Murray from SAC said producers should be aware of this potential problem and ensure that the recycled plaster board is stored and used in a way which completely avoids any potential contamination of slurry supplies.

He added that farmers should also take all animals out of the building and open all ventilation and doors before they start emptying slurry stores. Farmers and farm workers should avoid entering any building when the pump mixing the slurry or emptying the store is working.

Bob Carruth for NFU Scotland echoed this safety call, describing it as a timely reminder of the “dangers to man and beast from mixing slurry in an enclosed space”.

He added that another case had been reported to the Union where nine dairy cattle died on a Lanarkshire farm last week as a result of the toxic gas generated by slurry mixing.